Date: Sat, 13 Jun 2015 12:18:32 +0300
On 12.06.2015 18:58, "Alexander Götzelmann
(alexander.goetzelmann_at_hs-furtwangen.de)" wrote:
>
> Dear FLUKA- Users,
>
> Object of my Simulation is a Container for radioactive waste (=boron
> water); Co-60 volume beam. I want to score the fluence (caused by
> primaries) outside the container. For scoring I created a sphere of
> air und used USRTRACK to score the fluence inside this sphere.
>
> I want to apply Importance Biasing on my Simulation. I want good
> statistics only in the direction of the detector, so I cut a part of
> the wall in several layers (each has the thickness of one
> half-value-layer). With each layer I doubled the Importance to
> compensate the attenuation.
>
> I run the simulation with 5*200000 Primarys. The USRBIN-plot seems
> strange to me. Am I right in the assumption, that despite the too
> small number of primaries, the USRBIN-plot should show a much larger
> fluence in the direction of my interest.
>
> My suspicion is that my BIASING-Cards are ignored by FLUKA?!
> Please can somebody explain the problem and optimally correct my
> inpit-file (see the attachment).
>
> Best regards,
> Alexander
>
Dear Alexander,
1. Because you are using fractions of materials in your compound cards,
the materials must be mass mixtures instead of atoms.
* ..+....1....+....2....+....3....+....4....+....5....+....6....+....7..
MATERIAL 6. 1.7 Carbon
MATERIAL 14. 2.33 Silicium
MATERIAL 15. 2.2 Phospor
MATERIAL 16. 2.0 Sulfur
MATERIAL 24. 7.18 Chromium
MATERIAL 25. 7.44 Mangan
MATERIAL 26. 7.874 Ferrum
MATERIAL 28. 8.902 Nickel
MATERIAL 29. 8.960 Copper
* Material-Card fpr Barrel wall
MATERIAL 7.8 EISEN
COMPOUND -.0091831 Carbon -.0037122 Chromium -0.0108 SiliciumEISEN
COMPOUND -0.01305 Mangan-5.3414E-4 Phospor -0.95192 FerrumEISEN
COMPOUND -4.2997E-4 Sulfur -.0051678 Nickel -0.005207 CopperEISEN
MATERIAL 7. 0.001165 Nitrogen
MATERIAL 8. 0.001332 Oxygen
MATERIAL 18. 0.001662 Argon
MATERIAL 1. 0.000088 Hydrogen
MATERIAL 5. 2.37 Bor
* Material-Card for Air inside Barrel
MATERIAL 0.0013 LUFT
COMPOUND -0.00015 Carbon -0.21075 Oxygen -0.78443 NitrogenLUFT
COMPOUND -0.004671 Argon LUFT
* Material-Card for boron-water
MATERIAL 1.5 BORSAURE
COMPOUND -0.42857 Hydrogen -0.14286 Bor -0.42857
OxygenBORSAURE
2. You didn't switch on biasing in RADDECAY card. Then use EMF-BIAS,
WW-FACTO, WW-THRES
3. Even without any biasing, just increasing number of primaries up 10^6
with 4 threads here is what i got
Best regards,
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(image/png attachment: BRUCAB150mitGeoOp_53_plot.png)